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Ten mistakes AI makes in spreadsheets when nobody checks
A spreadsheet an AI made looks finished whether it’s right or not. The columns are neat, the totals are there, and the mistakes look exactly like everything else. Here are ten that slip through most often, and how to spot each one.
1. A row left out
A transaction, an invoice or a lease that’s in your documents and not in the sheet. Nothing looks missing, because the totals add up what is there. Spot it: count what your documents hold and compare.
2. A row made up
A row that’s in none of your documents, often one that makes a total come out right. Spot it: pick rows at random and find each one in your documents.
3. A row counted twice
The same item twice, often where a document runs onto a second page. Spot it: sort by amount and date and look for pairs.
4. A figure misread
A 7 read as a 1, a decimal point moved, or a figure taken from the wrong line. Spot it: check the biggest figures against your documents first.
5. Money in turned into money out
A deposit shown as a payment, a credit as a debit, a refund as a sale. The amount is right and the sign is wrong, so the total is off by twice the amount. Spot it: check the direction of the largest items.
6. A date moved
A day off, or month and day switched, which can move an item into the wrong month or the wrong bucket. Spot it: check the dates near the start and the end of each month.
7. A total that stops short
A total whose range misses a row, or adds the wrong column. It still looks like a total. Spot it: click each total and look at what it adds.
8. A number typed over a formula
The sheet shows a figure its formula wouldn’t give, because the AI typed the number in. Change an input and the figure doesn’t move. Spot it: recalculate and compare.
9. Figures that don’t follow from one another
Debits that don’t equal credits, an amount that isn’t quantity times price, a balance that doesn’t follow from the row above. Spot it: work out a few of them yourself.
10. A chart that shows old figures
A chart drawn before the figures changed, or one that stops a row short. It still looks like a chart of your figures. Spot it: compare the chart’s last point with the last row.
For the checks in the order that catches the most, see How to check work an AI made for you.